Information processing system and information processing method

Abstract

To provide an information processing system which can process processing object information, while maintaining confidentiality of the processing object information.SOLUTION: An information processing system includes: a first information terminal 11; and a second information terminal which is independent from the first information terminal and capable of communicating with the first information terminal via a network. The information processing system includes: a first encryption information generating section 110 which is provided in the first information terminal 11 in order to generate first encryption information that is encrypted information of processing object information, for a plurality of processing object information pieces respectively; a second encryption information generating section which is provided in the second information terminal in order to generate second encryption information that is information processed without applying decryption to a plurality of first encryption information pieces; and a decryption processing section 111 which is provided in the first information terminal 11 in order to apply decryption to the second encryption information and acquire processing result information.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005] , , ,

[0001] The present invention relates to an information processing system and the like that perform various processes such as analysis on encrypted information to be processed transmitted from one information terminal on another information terminal.

Background Art

[0002] In recent years, with the development of information and communication technologies, services for managing or analyzing information possessed by individuals, companies, etc. and performing predetermined processes such as these have become widespread. At this time, individuals and companies need to transmit information from information terminals possessed by the individuals and companies to information terminals of service providers. In transmitting information as described above, it is common to encrypt the information in order to ensure security.

[0003] Patent Document 1 discloses a system including an information processing server that receives encrypted information transmitted from an information processing terminal on the user side (individual or company side), analyzes the encrypted information, generates an encrypted index as an analysis result in an encrypted state, and returns the encrypted index to the information processing terminal. According to this system, it is possible to perform predetermined processing of the data without disclosing confidential information to service managers (service providers), etc. who are administrators of the server.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, according to the system disclosed in Patent Document 1, in order to perform analysis of the information to be analyzed (information to be processed), pre-processing such as word classification using a dictionary is performed on the server side (service provider side). At this time, some information is decoded, so the confidentiality of the information to be analyzed cannot be fully guaranteed. In other words, there is a problem in that it is not possible to perform analysis of the information to be analyzed while maintaining its confidentiality.

[0006] The present invention has been made in view of the above points, and aims to provide an information processing system and an information processing method that can perform predetermined processing, including analysis, on information to be processed while maintaining the confidentiality of the information to be processed. [Means for solving the problem]

[0007] The information processing system of the present invention is The system comprises a first information terminal and a second information terminal that is independent of the first information terminal and capable of communicating with the first information terminal, wherein the second information terminal receives a plurality of information to be processed transmitted from the first information terminal. For each of these, the first encrypted information is the information obtained by encrypting the information to be processed. An information processing system that performs a predetermined process on the first information terminal and obtains processing result information which is the result of the predetermined process, The first information terminal includes a first encryption information generation unit which generates first encrypted information, which is information obtained by encrypting the information to be processed, for each of the plurality of information to be processed; A second encryption information generation unit is provided in the second information terminal and generates second encryption information which is information obtained by performing the predetermined processing on the plurality of first encryption information without decrypting the plurality of first encryption information, The first information terminal includes a decryption processing unit that decrypts the second encrypted information and obtains the processing result information, The first encryption information generation unit, A word extraction unit that extracts multiple words contained in each of the multiple pieces of information to be processed, A frequency information generation unit generates frequency information, which is information relating to the frequency of occurrence of a word in the processing target information, based on the number of occurrences of each of the multiple words in the processing target information, for each of the multiple pieces of processing target information. For each of the extracted plurality of words, a correspondence information generation unit generates correspondence information which is information representing the correspondence between the word and the string corresponding to that word, The system includes a first encryption processing unit that encrypts the frequency information to obtain the first encrypted information by converting a plurality of words contained in the frequency information based on the corresponding information, The decryption processing unit decrypts the second encrypted information based on the correspondence information and obtains the processing result information.It is characterized by the following:

[0008] In this information processing system configuration, the information to be processed is encrypted at the first information terminal and transmitted to the second information terminal. At the second information terminal, predetermined processing is performed on the encrypted information without decryption, and the result of that processing, the second encrypted information, is generated. Subsequently, the second encrypted information is decrypted at the first information terminal, and only then can the processing result be obtained.

[0009] Therefore, in processing at the second information terminal, the information being processed itself, and the specific content of its processing results, cannot be grasped even if they are accessed at any point in the processing process. Consequently, this information processing system allows for the processing of information while maintaining its confidentiality. Furthermore, in an information processing system with this configuration, the first encrypted information generation unit (and by extension, the first information terminal) generates frequency information based on the number of occurrences of multiple words included in the information to be processed, and the information obtained by encrypting this frequency information is designated as the first encrypted information. In other words, the first encrypted information has a smaller data size compared to the information obtained by encrypting the entire text of the information to be processed. This reduces the load during transmission to the second information terminal and during processing at the second information terminal. Furthermore, information encrypted in this way, such as frequency data, is more confidential than information that is simply encrypted as the data being processed. This allows for a high level of confidentiality to be maintained for the data being processed.

[0010] In this information processing system of the present invention, Preferably, the predetermined processing includes at least one of analysis, interpretation, statistics, and aggregation.

[0015] Furthermore, in the information processing system of the present invention, It is preferable that the corresponding information generation unit generates new corresponding information using a different string from the string used in the corresponding information before the change when the processing target information included in the plurality of processing target information changes.

[0016] In an information processing system with this configuration, the corresponding information changes each time the population of information to be processed changes, and the method of encrypting the frequency information also changes. Therefore, this information processing system can maintain a high level of confidentiality for the information to be processed.

[0017] Also, in the information processing system of the present invention, It is preferable that the correspondence information generation unit generates the correspondence information using a character string consisting of alphabets.

[0018] A character string consisting of alphabets has a smaller data amount compared to Chinese characters and the like. Therefore, when the correspondence information is generated by a character string consisting of alphabets in this way, the data amount of the frequency information encrypted by the correspondence information can also be reduced. As a result, the load during transmission to the second information terminal and during processing in the second information terminal can be reduced.

[0019] Also, in the information processing system of the present invention, The first encryption information generation unit has a dictionary data storage unit that stores dictionary data which is data indicating the correlation between each of the plurality of words, It is preferable that the word extraction unit extracts the words included in each of the plurality of processing target information using the dictionary data.

[0020] According to the information processing system having such a configuration, dictionary data that is the basis for encryption processing is provided in the first information terminal including the first encryption information generation unit. The dictionary data can be easily updated by the user of the first information terminal. Therefore, by referring to the dictionary data, word information can be appropriately extracted from the processing target information. As a result, more detailed processing can be performed.

[0021] Also, in the information processing system of the present invention, Each of the plurality of processing target information includes attribute information that is information representing different attributes for each processing target information, The first encryption information generation unit has an ID assignment unit that assigns an ID to each of the plurality of processing target information, and a communication unit that associates the ID corresponding to the first encryption information with each of the plurality of first encryption information and transmits it to the second information terminal. The second encryption information generation unit processes a plurality of first encryption information associated with the ID to generate the second encryption information, The decryption processing unit preferably decrypts the second encrypted information, obtains the processing result information, and assigns the attribute information to the processing result information based on the ID.

[0022] The information to be processed includes information that is not necessary for the processing itself, but is useful for referencing after processing. Therefore, by separating the information contained in the information to be processed into an ID that identifies the information to be processed and attribute information, and by configuring the system so that the associated ID does not change before or after processing, it becomes possible to process only the information necessary for processing (i.e., information excluding attribute information) from the information to be processed, and then add attribute information later by referring to the ID.

[0023] This allows for a higher level of confidentiality of the information being processed, as attribute information is removed. Furthermore, it reduces the load during transmission to the second information terminal and during processing at the second information terminal.

[0024] Furthermore, the information processing method of the present invention is The second information terminal receives multiple pieces of information to be processed from the first information terminal. For each of these, the first encrypted information is the information obtained by encrypting the information to be processed. An information processing method comprising performing a predetermined process on the subject, wherein the first information terminal acquires processing result information which is the result of the predetermined process, For each of the aforementioned plurality of information to be processed, the first information terminal generates first encrypted information, which is information obtained by encrypting the information to be processed. The steps include generating a second encrypted information in the second information terminal, which is information obtained by performing the predetermined processing on the plurality of first encrypted information without decrypting the plurality of first encrypted information, The process includes the step of decrypting the second encrypted information and obtaining the processing result information at the first information terminal. 、 For each of the aforementioned plurality of information to be processed, the step of generating first encrypted information, which is information obtained by encrypting the information to be processed, at the first information terminal is: A word extraction step of extracting multiple words contained in each of the multiple pieces of information to be processed, A frequency information generation step for each of the plurality of information to be processed, which generates frequency information that is information relating to the frequency of occurrence of each of the plurality of words in the information to be processed, based on the number of occurrences of each of the plurality of words. For each of the extracted plurality of words, a correspondence information generation step is to generate correspondence information which is information representing the correspondence relationship between the word and the string corresponding to that word, The process includes a first encryption step of encrypting the frequency information to obtain the first encrypted information by converting a plurality of words contained in the frequency information based on the corresponding information, The step of decrypting the second encrypted information and obtaining the processing result information at the first information terminal involves decrypting the second encrypted information and obtaining the processing result information based on the corresponding information. It is characterized by the following: [Brief explanation of the drawing]

[0025] [Figure 1] This is a schematic diagram showing the configuration of the information processing system of the present invention. [Figure 2] This is a block diagram showing the functional configuration of the first information terminal of the information processing system of the present invention. [Figure 3] Block diagram showing the functional configuration of the second information terminal of the information processing system of the present invention. [Figure 4] This is a sequence diagram showing a series of control processes for encryption and information analysis performed by the information processing system of the present invention. [Figure 5] This is a flowchart showing the control process performed by the first information terminal to generate first encrypted information in the information processing system of the present invention. [Figure 6] This figure shows an example of textual information. [Figure 7] This figure shows an example of frequency information. [Figure 8] This figure shows an example of correspondence information. [Figure 9] This figure shows an example of the first encrypted information. [Figure 10] This figure shows an example of the second type of encrypted information. [Figure 11] This figure shows an example of the analysis results. [Modes for carrying out the invention]

[0026] (Configuration of Information Processing System 1) An information processing system 1 according to one embodiment of the present invention will be described in the following description and drawings. In this embodiment, the information analysis process as a predetermined process will be described as an example. As shown in Figure 1, the information processing system 1 of this embodiment includes a first information terminal 11 and a second information terminal 12. The first information terminal 11 and the second information terminal 12 are independent of each other.

[0027] Furthermore, the first information terminal 11 and the second information terminal 12 are each connected to each other via a network 13, enabling communication. The network 13 consists of the Internet and a LAN, etc. The first information terminal 11 is a PC (Personal Computer), and the second information terminal 12 is a server. Note that the first information terminal 11 may be an information terminal other than a PC, such as a smartphone, tablet, or server, and the second information terminal 12 may be an information terminal other than a server, such as a PC, smartphone, or tablet.

[0028] The first information terminal 11 is composed of a CPU, memory, I / O interface, and storage devices such as ROM, RAM, and HDD, and performs various control processes such as encryption, decryption, and pre-analysis processing, which will be described later. As shown in Figure 2, the first information terminal 11 includes a first encryption information generation unit 110 and a decryption processing unit 111.

[0029] The first encrypted information generation unit 110 consists of a word extraction unit 1101, a frequency information creation unit 1102, a correspondence information generation unit 1103, a first encrypted processing unit 1104, a dictionary data storage unit 1105, an ID assignment unit 1106, a communication unit 1107, and the like.

[0030] As described later, the first encrypted information generation unit 110 performs encryption and analysis processing to prepare the information to be analyzed (information to be processed), as shown in Figure 6, owned by the owner of the first information terminal 11, for analysis by the second information terminal 12.

[0031] The word extraction unit 1101 extracts words from the specified information to be analyzed, as will be described later. Specifically, the word extraction unit 1101 uses the word dictionary data and word extraction program stored in the dictionary data storage unit 1105 to divide the text into words and extract the words to be used for text analysis.

[0032] As described later, the frequency information generation unit 1102 aggregates the occurrence frequency of each word divided by the word extraction unit 1101 and generates frequency information, which is information relating to the occurrence frequency of words.

[0033] As will be described later, the correspondence information generation unit 1103 generates correspondence information for each word that has been divided by the word extraction unit 1101, which is information that represents the correspondence between each word and a predetermined string corresponding to that word.

[0034] As described later, the first encryption processing unit 1104 converts each of the multiple words included in the frequency information generated by the frequency information creation unit 1102 based on the correspondence information generated by the correspondence information generation unit 1103, and generates first encrypted information.

[0035] As will be described later, the dictionary data storage unit 1105 is a database for processing by the word extraction unit 1101, and stores a word dictionary (not shown) containing word information used for word extraction.

[0036] As will be described later, the ID assignment unit 1106 assigns an ID (see Figure 6) to each piece of information to be analyzed, and based on the ID, assigns attribute information to each piece of information to be analyzed, which includes information such as the document from which the words were extracted, the document creator, and the creation date.

[0037] The communication unit 1107 consists of communication devices and transmits the first encrypted information generated by the first information terminal 11 to the second information terminal 12 via the network 13. It also receives the second encrypted information generated by the second information terminal 12, which will be described later.

[0038] The decryption processing unit 111 decrypts the second encrypted information generated by the second information terminal 12 (described later) and obtains the analysis result information.

[0039] Next, the second information terminal 12 will be described. As shown in Figure 3, the second information terminal 12 is composed of a CPU, memory, I / O interface, and storage devices such as ROM, RAM, and HDD, and performs control processing such as analysis processing, which will be described later. The second information terminal 12 also includes a second encryption information generation unit 120 and a communication unit 121.

[0040] As described later, the second encryption information generation unit 120 analyzes multiple first encryption information and generates second encryption information, which is the result of the analysis.

[0041] The communication unit 121 is composed of communication devices and other components, and receives the first encrypted information generated by the first information terminal 11 via the network 13. It also transmits the second encrypted information generated by the second information terminal 12 to the first information terminal 11.

[0042] (Information processing method for Information Processing System 1) Next, the details of the various processes and functions in the information processing system 1 of this embodiment will be described. As described above, the information processing system 1 and information processing method according to this embodiment perform analysis processing on the information to be processed while maintaining the confidentiality of the information to be analyzed.

[0043] The following describes a series of control processes for encryption and information analysis performed by the information processing system 1, with reference to Figure 4. As shown in Figure 4, first, the first encrypted information is generated by the first information terminal 11 (Figure 4 / STEP 1). Specifically, this process is carried out as shown in Figure 5.

[0044] As shown in Figure 5, initially, words are extracted from the information to be analyzed, as specified by the owner of the first information terminal 11 (Figure 5 / STEP 11).

[0045] Here, as shown in Figure 6, the information to be analyzed consists of multiple sentences composed of multiple words. In this case, word information is obtained from the sentences using a predetermined analysis algorithm based on predetermined dictionary data. Here, the dictionary data is data that shows the correlation between each of the multiple words.

[0046] In this embodiment, an example is disclosed in which the information to be analyzed is Japanese text information, but the information to be analyzed in the present invention is not limited to Japanese text information. For example, it may be a predetermined foreign language other than Japanese, such as English, Chinese, or French, or it may be text information containing multiple languages ​​(for example, text information consisting of English and Japanese). In addition, other types of information to be analyzed besides text information may be used, such as image information, survey information (aggregated information), purchase information, and customer information.

[0047] Furthermore, the dictionary data is stored in the first information terminal 11. It is preferable to use dictionary data issued by administrative agencies or international organizations such as the IPA (Information-technology Promotion Agency, Japan). In addition to the IPA, the owner of the first information terminal 11 can also improve the accuracy of word extraction by preparing their own dictionary data. Furthermore, by setting stop words in the dictionary data, it is possible to prevent the extraction of words of particularly high confidentiality. The dictionary data can also be configured to be updatable. This improves the accuracy of word extraction because the latest word information is reflected in the dictionary data. In addition, when transmitting to the second information terminal 12, which will be described later, it becomes unnecessary to transmit unnecessary words and stop words, and it becomes unnecessary to transmit all duplicate words. Therefore, the amount of data is reduced compared to when all text information is transmitted, and the analysis and communication speed can be increased.

[0048] Furthermore, morphological analysis is preferably used as the word extraction method (extraction program). When the textual information is in Japanese, it is preferable, but not limited to, to use existing morphological analysis software such as MeCab, ChaSen, Janome, or Sudachi for morphological analysis. The present invention can also be implemented in languages ​​other than Japanese, and appropriate morphological analysis may be used in each language. Moreover, the word extraction method is not limited to morphological analysis, and any analysis method that is appropriate for those skilled in the art, such as rule-based natural language processing, may be used.

[0049] Once words are extracted as described above, frequency information is then generated for each extracted word (Figure 5 / STEP 12). As shown in Figure 7, the frequency information represents the frequency of occurrence of each word in the text information. In Figure 7, only ID·Data1 from Figure 6 is shown as frequency information, but frequency information is similarly created for multiple text information items assigned to each ID. In the following explanation, only ID·Data1 will be used as the subject.

[0050] Furthermore, frequency information may include not only information representing the occurrence of a word in each sentence, but also presence information, which represents the degree of presence of each word in each sentence. Here, presence is a numerical value that quantifies whether a given word is widely used in multiple documents or only in a specific document. In this case, presence may be quantified based on multiple paragraphs or IDs, rather than on multiple documents.

[0051] Next, for each of the extracted words, correspondence information is generated, which is information representing the correspondence between the word and the corresponding string (Figure 5 / STEP 13). At this time, as shown in Figure 8, the correspondence information generation unit 1103 generates the correspondence information using a string consisting of alphabets. However, Response The method of generating information is not limited to this. In addition to the alphabet, a string containing at least one character from numbers, symbols, and the alphabet may be generated as corresponding information.

[0052] While there are no particular limitations on the method of generating strings, from the standpoint of ensuring confidentiality, it is preferable to use a different string as the corresponding information after a change when the parsed information included in multiple parsed information items changes. In other words, even for the same word, it is preferable to assign a different string if it is a sentence information or parsed information with a different ID. Furthermore, from the standpoint of confidentiality, it is preferable to generate the strings randomly based on random numbers, but a person skilled in the art may generate them using any method.

[0053] Next, the frequency information is encrypted by converting multiple words contained in the frequency information based on the corresponding information, thereby generating the first encrypted information (Figure 5 / STEP 14). As shown in Figure 9, the first encrypted information consists of the encrypted string and information indicating the frequency.

[0054] After the first encrypted information, which is encrypted frequency information, is generated, the first encrypted information is transmitted from the first information terminal 11 to the second information terminal 12 via the network 13, along with an ID, by an operation by the owner of the first information terminal 11 (Figure 5 / STEP 15). The ID is linked to attribute information, which is information that represents different attributes for each piece of information to be analyzed, and is attached to the text information and transmitted simultaneously. In this embodiment, an example is shown in which the ID is transmitted together with the first encrypted information, but the generation and transmission of the ID may be omitted.

[0055] In this case, the first encrypted information may be transmitted by the owner's operation, or it may be transmitted to the second information terminal 12 simultaneously with its generation by predetermined control.

[0056] Returning to Figure 4, when the second information terminal 12 receives both the first encrypted information and the ID, the second information terminal 12 generates the second encrypted information based on the first encrypted information (Figure 4 / STEP2). At this time, the second information terminal 12 generates the second encrypted information by analyzing the first encrypted information using a predetermined analysis method.

[0057] Specifically, as shown in Figure 10, the second encrypted information is generated as coordinate information (coordinate information in the overview) obtained by analyzing the feature quantities (coordinates of each sentence) of each encrypted string based on the encrypted frequency information, which is the first encrypted information. Note that the second encrypted information is not limited to coordinate information; it may also be the overview itself. Furthermore, the second encrypted information is not limited to these examples; it may be any information obtained by aggregating the frequency of words in the document and analyzing it on the second information terminal 12.

[0058] Furthermore, in this analysis, if multiple sets of first encrypted information are received, the similarity of each set of first encrypted information may be analyzed. The analysis methods for features and similarity are not particularly limited, but methods such as the tf-idf method, Okapi BM25, and Bag of Words may be used as feature analysis methods. Alternatively, the dimensionality of the initial features may be reduced using singular value decomposition or principal component analysis, such as LDA (Latent Dirichlet Allocation), and the features may be analyzed based on the reduced dimensionality. As for the similarity analysis method, cosine similarity and Euclidean distance may be calculated based on the features obtained by the methods described above. Also, when analyzing multiple sentences, the similarity may be represented not in matrix form, but as XY coordinates as a projection of two-dimensional coordinates (see Figure 10). Furthermore, compound words consisting of multiple characters may be generated simultaneously (see Figure 10). By generating compound words, the owner of the first information terminal 11 can more easily grasp the information in the sentences.

[0059] When the second encrypted information is generated in the second information terminal 12, as shown in Figure 4, the second encrypted information and ID are transmitted to the first information terminal 11 by operation of the owner of the second information terminal 12 or by control of the second information terminal 12.

[0060] When the first information terminal 11 receives both the second encrypted information and the ID, the first information terminal 11 decrypts the second encrypted information to obtain the information to be analyzed (Figure 4 / STEP3). At this time, the second encrypted information is decrypted using the encryption key (corresponding information mentioned above) generated during the generation of the first encrypted information. As a result, the owner of the first information terminal 11 can obtain the analysis results shown in Figure 11. Therefore, the information can be obtained only by the owner of the first information terminal 11 without being leaked to the owner of the second information terminal 12 or to anyone who illegally intercepted the network 13.

[0061] Furthermore, at this time, it becomes possible to easily check attribute information linked to the analysis results (such as the original document, the document creator, and the creation date) based on the ID assigned to the analysis results. [Explanation of Symbols]

[0062] 1. Information processing system, 11. First information terminal, 12. Second information terminal, 13. Network, 110. First encrypted information generation unit, 111. Decryption processing unit, 120. Second encrypted information generation unit, 121. Communication unit (second information terminal), 1101. Word extraction unit, 1102. Frequency information creation unit, 1103. Correspondence information generation unit, 1104. First encrypted processing unit, 1105. Dictionary data storage unit, 1106. ID assignment unit, 1107. Communication unit (first information terminal).

Claims

1. An information processing system comprising a first information terminal and a second information terminal independent of the first information terminal and capable of communicating with the first information terminal, wherein the second information terminal performs predetermined processing on first encrypted information, which is encrypted information of each of a plurality of processing target information transmitted from the first information terminal, and the first information terminal acquires processing result information, which is the result of said predetermined processing, The first information terminal includes a first encryption information generation unit which generates first encrypted information, which is information obtained by encrypting the information to be processed, for each of the plurality of information to be processed. A second encryption information generation unit is provided in the second information terminal and generates second encryption information which is information obtained by performing the predetermined processing on the plurality of first encryption information without decrypting the plurality of first encryption information, The first information terminal includes a decryption processing unit that decrypts the second encrypted information and obtains the processing result information, The first encryption information generation unit, A word extraction unit that extracts multiple words contained in each of the multiple pieces of information to be processed, A frequency information generation unit generates frequency information, which is information relating to the frequency of occurrence of a word in the processing target information, based on the number of occurrences of each of the multiple words in the processing target information, for each of the multiple pieces of processing target information. For each of the extracted plurality of words, a correspondence information generation unit generates correspondence information which is information representing the correspondence between the word and the string corresponding to that word, The system includes a first encryption processing unit that encrypts the frequency information to obtain the first encrypted information by converting a plurality of words contained in the frequency information based on the corresponding information, The decryption processing unit is characterized by decrypting the second encrypted information based on the correspondence information and obtaining the processing result information.

2. In the information processing system described in claim 1, An information processing system characterized in that the predetermined processing includes at least one of analysis, analysis, statistics, and aggregation.

3. In the information processing system described in claim 1, The information processing system is characterized in that, when the processing target information included in the plurality of processing target information changes, the corresponding information generation unit generates new corresponding information using a different string from the string used in the corresponding information before the change.

4. In the information processing system described in claim 1, The information processing system is characterized in that the corresponding information generation unit generates the corresponding information using a string of letters.

5. In the information processing system described in claim 1, The first encrypted information generation unit has a dictionary data storage unit that stores dictionary data which is data showing the correlation between each of the plurality of words, The information processing system is characterized in that the word extraction unit extracts words contained in each of the multiple pieces of information to be processed using the dictionary data.

6. In the information processing system described in claim 1, Each of the aforementioned plurality of information to be processed includes attribute information which represents different attributes for each piece of information to be processed. The first encrypted information generation unit includes an ID assignment unit that assigns an ID to each of the plurality of processing target information, and a communication unit that associates the ID corresponding to each of the plurality of first encrypted information with the second information terminal, The second encryption information generation unit processes a plurality of the first encryption information associated with the ID to generate the second encryption information, The decryption processing unit is characterized by decrypting the second encrypted information, obtaining the processing result information, and assigning the attribute information to the processing result information based on the ID.

7. An information processing method comprising: a second information terminal performing a predetermined process on first encrypted information, which is information obtained by encrypting each of a plurality of processing target information transmitted from a first information terminal, and the first information terminal obtaining processing result information, which is the result of the predetermined process, For each of the aforementioned plurality of information to be processed, the first information terminal generates first encrypted information, which is information obtained by encrypting the information to be processed. The steps include generating a second encrypted information in the second information terminal, which is information obtained by performing the predetermined processing on the plurality of first encrypted information without decrypting the plurality of first encrypted information, The process includes the step of decrypting the second encrypted information and obtaining the processing result information at the first information terminal, For each of the aforementioned plurality of information to be processed, the step of generating first encrypted information, which is information obtained by encrypting the information to be processed, at the first information terminal is: A word extraction step of extracting multiple words contained in each of the multiple pieces of information to be processed, A frequency information generation step for each of the plurality of information to be processed, which generates frequency information that is information relating to the frequency of occurrence of each of the plurality of words in the information to be processed, based on the number of occurrences of each of the plurality of words. For each of the extracted plurality of words, a correspondence information generation step is to generate correspondence information which is information representing the correspondence relationship between the word and the string corresponding to that word, The process includes a first encryption step of encrypting the frequency information to obtain the first encrypted information by converting a plurality of words contained in the frequency information based on the corresponding information, The step of decrypting the second encrypted information and obtaining the processing result information at the first information terminal is characterized in that the second encrypted information is decrypted based on the corresponding information and the processing result information is obtained.

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